Vanadate-Mediated Mismatch Configuration over the Reconstructed Nickel-Iron Electrocatalyst for Boosting Alkaline Oxygen Evolution

During the oxygen evolution reaction (OER), catalyst candidates that can fully trigger self-reconstruction to derive active species with favorable configurations are expected to overcome the sluggish reaction kinetics. Herein, we innovatively propose the introduction of heterogeneous vanadate dopants into nickel-iron alloy precatalysts, where the crystal mismatch structure induces local electron delocalization in the hexagonal close packed alloy phase, thereby facilitating adequate electrochemical reconstruction to form (oxy)hydroxides as the real catalytic species. Simultaneously, the participation of vanadate in the reconstruction also triggers mismatch in the derived (oxy)hydroxides, reinforcing the metal-oxygen covalence, so that lattice oxygen activation is kinetically favorable and facilitates the OER via the lattice oxygen pathway. Optimized reconstructed catalyst r-NiFeVO_x-NF exhibits a low overpotential of 220 mV at current densities of 10 mA cm^-2 and considerably stable operation. Our study opens up opportunities for achieving robust OER performance through the design and fabrication of the mismatch catalytic configuration.